“…Very often sliding systems are assessed indirectly by evaluating the quality of machining parts [3]. Direct assessment of the components of the sliding system can be performed using both off-line and on-line techniques, based on methods such as vibration analysis [4][5][6][7], laser interferometry [8,9], noise analysis [10,11], visual inspection [12,13], temperature monitoring [14,15], acoustic emission monitoring [16,17], motor current signature analysis [18,19] and thermal imaging [20][21][22].…”